1. Field of the Invention
This invention relates to an optical connector which connects to an optical fiber connector plug a reception/transmission module (optical module) or optical fiber cable for use as an optical communication terminal.
2. Description of the Prior Art
In recent years, optical communications using optical fibers have been rapidly spread into utilization in the broad range of application fields. The optical fiber is extremely thin and hence difficult to completely couple thereto optical signals (reception/transmission signal). Meanwhile, if the optical fiber is incomplete in coupling, there requires output increase for the light,emitting device or sensitivity increase for the light receiving element. This however will result in cost increase.
In order to push ahead optical communications furthermore, it is desired to provide a high coupling degree of optical coupling to between an optical module or optical fiber cable and an optical fiber connector plug.
For connections between conventional optical fibers, there are prescriptions in JIS C5973-1990 on the shapes of optical connectors.
FIG. 8(A) illustrates a plug 1a. The plug 1a has a ferrule 2 held rotatable about an axis thereof by a spring 3. An optical fiber 4 (FIG. 8(C)) is held about a center of the ferrule 2. The ferrule 2 is surrounded around by a frame 5 having a recess 5a.
On the other hand, an adapter 1b, as shown in FIG. 8(B), has an integrally-formed member 6 having a sleeve holder 6a for holding a split sleeve 7 and a claw 6b for engagement with the recess 5a of the plug 1a of the frame 5. The integrally-formed member 6 is fixed within a case 8.
By inserting the plug 1a into the adapter 1b, the recess 5a of the frame 5 is fitted with the claw 6b. Thereupon, the ferrule 2 is adjusted for angular and positional deviation by the spring 3, as shown in FIG. 8(C). Furthermore, the optical fibers 4 are center-aligned by the split sleeve 7 and joined with each other.
In the prior art of FIG. 8, the sleeve holder 6a is formed separate from the case 8. Accordingly, the sleeve holder 6a in the case 8 is liable to deviate in position or angle.
Also, because the claw 6b of the adapter 1b is formed integral with the sleeve holder 6a, the claw 6b is low in positional or angular freedom. Consequently, if the integrally-formed member 6 deviates in position or angle when bonded to the case 8 as stated before, the claw 6b will also deviate in position or angle. Due to this, an imbalance force is applied to the plug 1a. As a result, the optical fibers 4 are impossible to be center-aligned completely. This results in loss of connection.
Furthermore, although the claw or engagement member 6b is formed of a plastic together with the sleeve holder 6a, the claw 6b requires elasticity for engagement with the recess 5a. Consequently, it is impossible for the claw to use a plastic usable at high temperature or employ a glass-fiber reinforced plastic. There accordingly is another problem that the prior art cannot withstand at such elevated temperature as is experienced during a solder reflow process to be conducted for mounting the optical connector onto a printed board.